religio-political organization founded in 1928 at Ismāʿīlīyāh, Egypt, by Ḥasan al-Bannāʾ. It advocated a return to the Qurʾān and the Ḥadīth as guidelines for a healthy, modern Islāmic (Islāmic world) society. The brotherhood spread rapidly throughout Egypt, the Sudan, Syria, Palestine, Lebanon, and North Africa.

After 1938 the Muslim Brotherhood began to politicize its outlook. It demanded purity of the Islāmic world and rejected westernization, secularization, and modernization. The brotherhood organized a terrorist arm, and when the Egyptian government seemed to weaken in the mid-1940s, the brotherhood posed a threat to the monarchy and the ruling Wafd Party. With the advent of the revolutionary regime in Egypt in 1952, the brotherhood retreated underground. An attempt to assassinate Egyptian president Gamal Abdel Nasser (Nasser, Gamal Abdel) in Alexandria on Oct. 26, 1954, led to the Muslim Brotherhood's forcible suppression. Six of its leaders were tried and executed for treason, and many others were imprisoned. In the 1960s and '70s the brotherhood's activities remained largely clandestine.

In the 1980s the Muslim Brotherhood experienced a renewal as part of the general upsurge of religious activity in Islāmic countries. The brotherhood's new adherents aimed to reorganize society and government according to Islāmic doctrines, and they were vehemently anti-Western. An uprising by the Muslim Brotherhood in the Syrian city of Ḥamāh in February 1982 was crushed by the government of Ḥafiz al-Assad at a cost of thousands of lives. The brotherhood revived in Egypt and Jordan in the same period, and beginning in the late 1980s it emerged to compete in legislative elections in those countries.